1. Field of the Invention
This invention relates to the field of insect control technology, and more specifically, to methods and apparatus for controlling termite activity, movement and population using radio waves (e.g. electromagnetic fields) within a certain frequency range. The methods and apparatus may be used to protect a structure from termite infestation.
2. Background of the Technology
Untreated termite infestations lead to irreversible structural damage in buildings throughout the world. As a result, a myriad of treatments to control or destroy termite populations have been developed. Because of the potential negative environmental impact of insecticides, environmentally friendly alternatives have been the primary focus of the latest research.
A significant amount of prior art focuses on the use of electromagnetic fields to control (repel and/or negatively affect) termites. U.S. Pat. No. 5,473,836, issued to Liu discloses a method for removing insects from “hidden places” by inducing an electromagnetic field to create physical vibrations. U.S. Pat. No. 5,930,946 issued to Mah discloses a method for creating an electromagnetic field to which pests react adversely. U.S. Pat. No. 5,442,876 issued to Pederson discloses a method for controlling termites by heating the area where termites are located to temperatures which are lethal to living organisms by means of electromagnetic energy. U.S. Pat. No. 4,870,779 issued to Bergerioux et al. discloses a method in which a low frequency, randomly varying magnetic field is generated by a device such that it interacts with the earth's geomagnetic field to eliminate (repel) rodents and similar pests located above and below ground level in the area surrounding the device.
The use of electrical energy has also been employed in efforts to eliminate (repel and/or negatively affect) termites. U.S. Pat. No. 5,210,719 issued to Lawrence discloses an apparatus and method which uses a sweep-frequency, high voltage generator coupled to an applicator gun for feeding electric power into pest-infested dielectrics, for example termite-infested wood. U.S. Pat. No. 4,366,644 issued to Lawrence discloses a method that involves the application of broadband radio frequency or multifrequency high-voltage electrical energy to termite shelter tubes, galleries and nests and to the bodies of termites in those areas. The '644 patent describes methods to kill termites directly by electroshock or indirectly by creating interference with the digestive processes of termites. U.S. Pat. No. 4,782,623 issued to Lawrence discloses an apparatus and method, which uses a phase-locked high voltage, high frequency pulse generator capable of “quasi-unlimited” power output and an applicator gun for feeding electric power into pest-infested dielectrics, for example termite infested wood. U.S. Pat. No. 4,223,468 issued to Lawrence discloses a method that involves killing termites by the application of broadband, high voltage electrical energy to habitats of termites.
The application of microwave energy has also been employed in the attempt to control (repel and/or negatively affect) termites. U.S. Pat. No. 5,575,106 issued to Martin et al. discloses a method of using low voltage “microwave horns” to kill termite populations. U.S. Pat. No. 5,896,696 issued to Stokes et al. discloses an apparatus and method for generating and radiating energy at specific wavelengths for the purpose of adversely affecting the nervous systems of “small insects.”
While these environmentally friendly methods of controlling termites have avoided the use of conventional pesticides, they have failed to adequately protect termite-susceptible structures from infestation. U.S. Pat. No. 6,837,001 to Amburgey et al. describes a method to attract termites to a selected area using radio waves and thereby provide protection from termites for other adjacent areas. The frequency of the radio waves ranged from about 1-100 megahertz with intensities 1-100 K watts.